Minimally invasive medical procedures can be used to dispose of problematic concretions that can develop in certain parts of the body, such as in the kidneys, pancreas, and gallbladder. Lithotripsy and ureteroscopy, for example, may be used to treat urinary calculi (e.g., kidney stones) in the ureter of patients. Lithotripsy is a medical procedure that uses energy in various forms, such as acoustic shock waves, pneumatic pulsation, electrical hydraulic shock waves, or laser beams to break up biological concretions such as urinary calculi (e.g., kidney stones). The force of the energy, when applied either extracorporeally or intracorporeally, usually in focused and continuous or successive bursts, divides a kidney stone into smaller fragments that may be extracted from the body or allowed to pass through urination.
Typically, a medical retrieval device, such as a surgical grasper or a metal wire basket, is used to capture a kidney stone in a retrieval assembly during a lithotripsy procedure. With the kidney stone held in position within the retrieval assembly, a lithotriptor, such as a laser lithotriptor, comes within the stone's proximity and fragments it. After the kidney stone is fragmented, the stone fragments can be removed by the same or a different medical retrieval device, or the fragments can be left in the body to be eliminated naturally.
In certain instances, intracorporeal fragmentation of urinary calculi can prove problematic in that stones and/or stone fragments in the ureter may become repositioned closer to and possibly migrate back toward the kidney, thereby requiring further medical intervention to prevent the aggravation of the patient's condition. In these circumstances, the same device or a different medical device may be deployed to control migration and aid in retrieval of fragmented stones. For example, an immobilization device may be deployed within a patient's body, independently or through the working channel of an endoscope, to act as a backstop to prevent upward migration of fragments resulting from a lithotripsy procedure.
These devices, while effective, have certain drawbacks. As physicians sometimes use different instruments to insert the medical retrieval device, lithotripter, and/or immobilization device into a patient's body, the exchange of instruments can cause trauma to the lining of a patient's ureter. Similarly, the exchange of medical devices such as, for example, a lithotripor and an immobilization and/or retrieval device, through a single working channel of, for example, an ureterscope, can prolong the duration of the surgical procedure. Consequently, it may be desirable to have an integrated assembly for preventing migration of stones and fragments, performing the lithotripsy procedure, and extracting residual fragments using a single device, so as to prevent the need for successive instrumentation.
Further, known medical devices for preventing migration of stones and fragments are often made of materials formed at least partially of metals and shape-memory materials such as stainless steel, nitinol, copper, cobalt, vanadium, chromium, iron or the like. The continued deployment, repositioning, and movement of these metallic materials can often cause undesired irritation and unnecessary trauma. Thus, it may be desirable to have alternative methods and devices for preventing upward migration of fragments, while limiting trauma to the patients.